1. Field of the Invention
The present invention relates to liquid crystal display (hereinafter LCD) display technology and associated 2D and 3D viewing of displayed images from the perspective and standpoint of a viewer disposed at various distances and angle of incidences from the LCD itself.
2. Related Art
In recent years, LCDs have been receiving attention as slim, large sized color screen displays, and are becoming increasingly common in business and consumer applications. LCDs are generally provided in electronic products, such as notebook computers, desktop monitors, televisions, digital cameras, DVD players, PDAs, mobile phones, portable gains, and car navigation systems, among other applications. Therefore, the ubiquitous application of liquid crystal technology has led to ever-increasing needs for consistent image display irrespective of viewer positioning away from the display, particularly in three-dimensional applications.
Conventional two-dimensional (“2D”)/three-dimensional (“3D”) displays utilize passive polarization, e.g., plane extension, separate light transmission, parallax units, and light concentration with lenticular sheets. However, fixed lenticular sheets and parallax units, can limit the scope and distance of human vision. Moreover, the fixed configuration prevents any adjustments to the displayed image. Accordingly, 3D displays are inherently limited in their applications in electronic devices.
As illustrated in FIGS. 1A-B, the Prior Art LCDs contains various upper, intermediary and lower basic photoactive units. FIG. 1A illustrates a conventional structure comprising a light guide unit 101 and light source 101(a), light diffuser 102, liquid crystal display unit 103, lenticular lens prism array 104, e.g., light concentrator. Toward the back of the entire LCD apparatus, the lower basic photoactive units, such as the diffuser, function to diffuse transmitted light by various means, such as plane extension, polarization, separate light transmission, and light barriers. Toward the front of the entire LCD apparatus, the upper basic photoactive unit has optical structures that function to concentrate transmitted light, e.g., lenticular sheets, wave transmitters, etc. The conventional structure contains an adjustable structure 105 disposed between the display unit and the light concentrator, as illustrated in FIG. 1A. Alternatively, the adjustable structure can be disposed between the display unit and the light concentrator, as well as the display unit and the light diffuser, as illustrated in FIG. 1B.
Alternatively, as illustrated in FIGS. 2A-2B, light-guide-diffusing units are also used to diffuse transmitted light in the Prior Art. This is in contrast to distinct light guide 101 and diffuser 102 units of FIGS. 1A-1B. Thus, the conventional structure comprises a combined light guide-light-diffusing unit 201, display unit 203, light concentrator 204, in addition to the adjustable structure unit 205 disposed between the display unit 203 and the light concentrator 204, as illustrated in FIG. 2A. Alternately, as illustrated in FIG. 2B, the adjustable structure 205 can be located between the light-guide-light-diffusing unit 201, as well as the display unit 203 and the light concentrator 204.
The prior art as recognized in U.S. Pat. No. 6,377,295B1 Zhiren Hu discloses a 2D/3D distance-adjustable display. FIGS. 3A-3B and 4A-4B illustrate a Prior Art construction for 3D display having adjustable light concentrator height. FIG. 3A shows an exemplary fixed 3D focal plane. As illustrated in FIG. 3A, the device contains light guide unit 301, light diffuser 302, display unit 303 and light concentrator 304. Adjustable structures 305 is included disposed between the display unit 303 and the light concentrator 304. The configuration permits the 3D focal plane 306 to be positioned at a predetermined distance away from the entire LCD apparatus. FIG. 3B illustrates the adjustable structure positioning the light concentrator 304 in such a manner to offset the 3D focal plane 306 for viewing.
FIG. 4 A-B shows an exemplary 3D focal plane that has been set based upon differentially adjusted electromechanical system components. FIG. 4A illustrates the device of FIGS. 3A-3B, which the device contains light guide unit 401, light diffuser 402, display unit 403 and light concentrator 404. Adjustable structure 405 is configured to permits the 3D focal plane 406 to be positioned at further extended distance away from the entire LCD apparatus, as compared to FIG. 3A. Projected upon the focal plane 406 is the resultant 3D image. FIG. 4B illustrates the adjustable structure 405 positioning the light concentrator 404 in such a manner with an alternate offset of the 3D focal plane 406 for viewing, as compared to FIG. 3B. FIG. 3A and FIG. 4A show the situation of various distance, while FIG. 3B and FIG. 4B show the situation of different angle.
According to Hu, the distance between 3D image displayed can be adjusted, using the adjustment structure according to viewer's location/position. The prior art adjustable structure 405 can be maneuvered using electromechanical means. The adjustable structure 405 are composed of lens arrays, which can be lenticular sheets. Lens array can be hologram array or parallax units. Importantly, it should be noted that the adjustable structure is always disposed on top of or above the display unit 403. Electromechanical transducers connected to mechanical transmitters are used to displace the lens array, lenticular sheets or parallax units. Thus, only an electromechanical structure is disclosed. Electromechanical transducers are comprised of stepper motors, servo motors, or voice coil stages. These means may include mechanical wheel devices or ball-shaped screw devices. The disclosed electromechanical means can be used only with the precise input of information about the precise static location/position of the viewer.
Currently, various electromechanical methods have been investigated in order to modify and adjust the distances between the lenticular sheets and the parallax units. These efforts at modifying the functionality of displays enable the adjustment of the scope and distance for proper human vision. However, the practical application of electromechanical methods have been complex, unreliable, convoluted, and characterized by low levels of accuracy and stability. Moreover, prior art 3D displays tend to have only found application in small palm or desktop electronic devices. Therefore, the application of 3D displays under the present state of the art is not cost effective and somewhat limited in practical embodiments.
Thus, a major disadvantage of the prior art LCDs lies in their requirement for the viewer make major neuro-physiological adjustments in order to view a displayed image depending on the distance from the display. This results in physiological strain and image quality degradation depending on the distance from the focal plan in both 2D, but also more pronounced in 3D displays.
Therefore, there is a present need for an improved apparatus and method for adjusting the viewing characteristic of the LCD itself, irrespective of the distance of the viewer from the focal plan. Further, given the increased application of 2D/3D LCD technology, it recognized that LCDs will be required that provide an increased efficacy in viewing from various distances and different angles from the display with a deleterious viewed image quality. Accordingly, the present invention provides such a precise and cost-effective solution.